Determination of carrier effective mass, impurity energy levels, and compensation ratio in Ga_4Se_3S layered crystals by Hall effect measurements

摘要

In this work, the dark electrical resistivity, charge carriers density and Hall mobility of Ga_4Se_3S single crystals have been measured and analyzed in the temperature region of 200-350 K. The data analyses have shown that this crystal exhibits an extrinsic n-type of conduction. The temperature-dependent dark electrical resistivity analysis reflected the existence of energy level as 0.31 eV. The temperature dependence of carrier density was analyzed by using the single donor-single acceptor model. The latter analysis allowed therndetermination of electron effective mass as 0.38m_0, hole effective mass as 0.42m_0, donor impurity energy level as 0.45 eV, acceptor-donor concentration ratio (N_a/N_d) as 0.97 and a donor-acceptor concentration difference as N_d -N_a = 1.5 × 10~(11) cm~(-3). The Hall mobility of Ga_4Se_3S is found to increase with decreasing temperature following a power law of slope of ～(-6.3). The abnormal behavior of mobility was attributed to the domination of phonon scattering and/or crystals anisotropy.